盐-水体系溶解平衡计算的自由能最小化及溶度积方法

根据电解质溶液的基本物理化学原理和近代电解质溶液理论的Pitzer离子相互作用模型,通过计算浓电解质溶液的活度系数和水的活度,研究了盐-水体系溶解平衡的计算方法.结果表明,体系Gibbs自由能最小化方法是计算盐-水体系溶解平衡的一种有效方法,其计算结果与溶度积法一致.     

甲醇-苯混合溶剂中NaI活度系数的测定与计算

测定了甲醇-苯-NaI体系在恒压条件下的汽液平衡数据,采用双标准检验法对数据进行检验,检验结果全部合格.应用P itzer强电解质在水溶液中的活度系数模型,采用全部合格的汽液平衡数据拟合出方程中的维利系数,从而获得在双液比固定条件下盐在甲醇-苯混合溶剂中的活度系数.计算结果表明,正常泡点温度下在具有固定双液比的甲醇-苯混合溶剂中,NaI的平均活度系数随盐浓度的增加先减小,经过一个极小值后又增加.     

气相色谱法测定非极性（弱极性）溶质在盐十环丁砜溶液中的无限稀释活度系数

以往,气相色谱法测定溶质的无限稀释热力学参数主要集中于单组分溶剂或混合非电解质溶剂为固定液的体系。对于非水电解质溶液为固定液的体系则很少涉及。本文将气相色谱法推广用于测定非极性、弱极性非电解质溶质在盐(NaI、KI、KCNS)十环丁砜溶液中的无限稀释活度系数γ_1~∞。     

混合溶剂中混合电解质活度系数的研究——HCl+NaCl+PrOH+H_2O体系,298.15K

电动势法是测定混合电解质活度系数时常用的主要方法,曾用这种方法对混合电解质水溶液活度系数作过火量的研究。可是,在有机溶剂和水的混合溶剂中混合电解质的电动势数据和活度系数数据却很少。Akerlof等人在这方面进行了开创性的研究工作,他们在恒定总     

拟静态沸点计法测定非水电解质溶液的渗透系数

本文将非分析循环沸点计［1，2］和拟静态方法[3]应用于非水电解质溶液体系的渗透系数的测定，建立了一套拟静态沸点计法测定非水电解质溶液渗透系数的实验装置．经NaCl、NaBr两个甲醇盐溶液体系的检验，相对标准误差小于1％，与传统的苦态法和等压法比较，拟静态沸点计法是一种快速、准确、方便的方法．用该装置分别测定了29巳15K时，＊d、Me。＊Q和BU4＊Br甲酸盐溶液渗透系数，实验值用Pitier方程关联，用关联得到的Pitier相互作用参数计算了盐的活度系数．1实验部分1．1实验原理在等温的条件下，电解质溶液处于汽液平衡时，如果测出…     

稀散金属化合物水溶液热力学研究Ⅰ.HCl+GaCl3+H2O体系

在HCl+GaCl3+H2O体系中,恒定五个总离子强度I=0.4,0.6,0.8,1.0,1.5 mol/kg,控制混合电解质中氯化镓离子强度分数YB=0.0, 0.1, 0.3, 0.5, 0.7,并在278.15～318.15 K范围内测定了五个温度的无液接电池:Pt|H2 (101.325 kPa)| HCl (mA), GaCl3 (mB), H2O|AgCl|Ag的电动势.根据150个实验点的电动势数据,确定了HCl的活度系数及其随氯化镓浓度变化规律,结果发现HCl活度系数遵守Harned规则.同时本文在Pitzer电解质溶液理论基础上提出了一个确定氯化镓的Pitzer参数和活度系数的方法,指出了氯化镓在这个混合电解质溶液中遵守扩展的Harned规则.     

298.15K下果糖水溶液中卤化钠单个离子活度系数

利用离子选择性电极和甘汞电极分别测定了NaX+果糖+水体系中的单个离子活度系数和离子平均活度系数.结果表明:基于Debye-Hückel扩展方程和Pitzer方程求得的单个离子活度系数彼此一致;由单个离子加合求得的与直接测定的平均离子活度系数也很一致;随果糖含量的增大,单个离子活度系数减小;在相同混合溶剂(果糖+水)和相等电解质浓度条件下,对于不同的NaX,Na+的活度系数大小顺序为NaFNaClNaBr.基于离子间的相互作用对结果进行了讨论.     

威尔逊方程能量参数的回归

目前利用单端无限稀释活度系数来求得整个浓度范围内的汽液平衡数据有一定的缺陷^[1,2]。本文由实验数据回归得威尔逊方程能量参数,并求得了与经典法测定的相一致的汽液平衡数据。     

含锂水盐体系热力学性质研究:LiCl-MgCl~2-H~O体系渗透系数和活度系数的等压测定

25℃下,用等压法测定了单盐水溶液(浓度范围分别为0.5-19.8mol.kg^-1,0.3-6.0mol.kg^-1)以及混合水溶液(离子强度范围为0.6-19.4mol.kg^-1)的水活度和渗透系数,同时测定了LiCl的溶解度.该体系的实验等水活度线符合本工作推导出的Zdanovskii规则扩展式,用Gibbs-Duhem方程和改进的Mckay-perring方法计算了单盐和混合盐水溶液的活度系数.由本实验获得的渗透系数拟合了Pitzer单盐和混合作用参数,检验了Pitzer方程对该体系渗透系数、活度系数和溶解度预测的适用性.用Pitzer方程取本工作得到的参数计算的溶解度与文献实验值基本一致.     

含锂水盐体系热力学性质研究:LiCl-MgCl~2-H~O体系渗透系数和活度系数的等压测定

25℃下,用等压法测定了单盐水溶液(浓度范围分别为0.5-19.8mol.kg^-1,0.3-6.0mol.kg^-1)以及混合水溶液(离子强度范围为0.6-19.4mol.kg^-1)的水活度和渗透系数,同时测定了LiCl的溶解度.该体系的实验等水活度线符合本工作推导出的Zdanovskii规则扩展式,用Gibbs-Duhem方程和改进的Mckay-perring方法计算了单盐和混合盐水溶液的活度系数.由本实验获得的渗透系数拟合了Pitzer单盐和混合作用参数,检验了Pitzer方程对该体系渗透系数、活度系数和溶解度预测的适用性.用Pitzer方程取本工作得到的参数计算的溶解度与文献实验值基本一致.     

Study of activity coefficients for sodium iodide in (methanol + benzene) system by (vapour + liquid) equilibrium measurements

By measuring the (vapour + liquid) equilibrium of {methanol (1) + benzene (2) + NaI} and testing the data using the ternary Gibbs–Duhem equation, the experimental results of the (vapour + liquid) equilibrium with thermodynamic consistency are obtained. It is supposed that the mean activity coefficients of NaI in (methanol + benzene) mixed solvents may be represented by a power series of salt concentration (m^1/2). Each parameter of the series was then obtained from the experimental results by the method of least squares. The calculated results show that the activity coefficients of NaI in (methanol + benzene) system with constant composition either decrease as the concentration increases, or decrease at first, then pass through a minimum and increase gradually again. This method is applicable to the determination of electrolytic activity coefficients in mixed non-aqueous solvents.     

The theoretical basis of mercurimetry in non-aqueous solutions

The methods for thermodynamic calculations of the equilibria in solutions of mercury salts and complexes are presented. The calculations of equilibrium constants in non-aqueous solvents are based on the transfer activity coefficients of mercury ions from water to the non-aqueous solvent. The dismutation and precipitation reaction constants are calculated, and the redox potentials of mercury systems are measured. Examples of analytical use of the thermodynamic functions of mercury salt solvation are given in the text.     

Solubilities of Hexaphenoxycyclotriphosphazene and Tri(2-cyanoethyl)phosphine in Selected Solvents: Measurement and Correlation

Solubilities of hexaphenoxycyclotriphosphazene and tri(2-cyanoethyl)phosphine in selected solvents were measured in this work using a static analytical method. The solubilities of a series of phosphorus-containing flame retardants in organic solvents and water were recently measured in our laboratory. Based on these data and the solid?Cliquid equilibrium equation for the solute, the activity coefficients of these flame retardants were derived in pure solvents. The Scatchard?CHildebrand activity coefficient model was used to correlate these activity coefficients and the solubility parameters of the solutes were obtained. With the help of the analysis of the solubility parameters for the solute and solvents, solubility enhancement can be achieved due to the occurrence of the synergetic effect of the mixed solvent.     

Isothermal vapor-liquid equilibria for the binary systems propylene-carbon dioxide,propylene-ethylene and propylene-ethane at high pressure

isothermal vapor-liquid equilibria for the binary systems propylene-carbon dioxide, propylene-ethylene and propylene-ethane have been measured at 283.15 and 298.15 K using a static method.The equilibrium data obtained have been correlated with the total-pressure method using both the Redlich-Kwong equation of state modified by Soave and the perturbation equation proposed by Gubbins and Twu. From normal probability plots of the residuals in the correlations versus the theoretical residuals in the normal distribution, the applicability of each of these two equations has been tested statistically.Furthermore, the fugacity coefficients calculated from the virial equation have been compared with those obtained from the correlations for the low-pressure regions.     

燃料馏分油气－液相平衡常数的测定与关联

实沸点蒸馏原油获得燃料馏分油。采用拟静态法测定不同沸程的22种燃料馏分油在系列温度下的泡点蒸气压，用Antoine方程关联蒸气压与温度的关系。在泡点压力分别为10 kPa、30 kPa、50 kPa、80 kPa和101.325 kPa时，按虚拟组分处理法计算了燃料宽馏分油中各虚拟组分的气-液相平衡常数，关联了气-液相平衡常数与虚拟组分的沸点以及相平衡温度、压力的关系，得到的表达式可以计算常压沸点范围在348.15 K至623.15 K间燃料宽馏分油的气-液相平衡常数，经180个数据点回归检验，平均误差为4.5%。     

The prediction of vapor-liquid equilibrium data from heat of mixing data for three non-ideal binary systems

The method of Hanks et al. was used with the heat of mixing data of McFall et al. for 1,3-butadiene + propylene, 1-butene + methyl tert.-butyl ether, and carbon disulfide + methanol to predict the vapor-liquid equilibrium behavior for these systems. The method involves curve-fitting an excess enthalpy model derived from an excess Gibbs energy model by means of the Gibbs-Helmholtz equation to the heat of mixing data, determining the adjustable parameters from this fit, and using the original excess Gibbs function equation to predict the vapor-liquid equilibrium behavior. The predicted vapor-liquid equilibrium values were compared with experimental values and good agreement was found.     

Excess molar volumes and isothermal vapor-liquid equilibrium in the binary system 1,1,1-trichloroethane with 1-chlorobutane and with pyridine at 25°C

Densities and vapor-liquid equilibrium were determined for 1-chlorobutane and pyridine with 1,1,1-trichloroethane at 25°C. From the experimental results, excess molal volumes and excess molar Gibbs energies were calculated. Information could be obtained about the possible interactions between the components of both binary systems. The Prigogine-Flory-Patterson theory was applied to calculate excess molar volumes. Liquid activity coefficients were calculated and correlated with different expressions existing in the literature.     

Vapor-liquid equilibria of the methanol-methyl methacrylate system at 313.15, 323.15 and 333.15 K

Isothermal vapor-liquid equilibrium data were measured for the methanol-methyl methacrylate system at 313.15, 323.15 and 333.15 K, using a modified Dvorak and Boublik recirculation still. Excess Gibbs free energies and liquid activity coefficients were calculated and correlated by a three-constant Redlich-Kister equation. A binary azeotrope exists at all three temperatures and its methanol concentration increases with increasing temperature.     

Determination and correlation of binary vapor-liquid equilibrium data

The Chao modification of the Redlich-Kister equation for correlating liquid activity coefficients is further modified to facilitate the evaluation of the constants. The determination of liquid activity coefficients at infinite dilutions by means of an ebulliometer with the consideration of vapor hold-up in the condenser is proposed. Both of these proposals are equally applicable to isothermal data and to isobaric data.For the purpose of illustration, vapor-liquid equilibrium data for the binary system acetone-methanol together with the azeotropic point and the liquid activity coefficients at infinite dilutions were determined at 760 Torr. The validity of the correlated data was confirmed with the enthalpies of mixing data at saturation, available in the literature.